I have no reason to doubt this...but I want to...but I can't...so I wont...and i'll play the next one when it comes out.
I wish it weren't true.. but KI really is that unbalanced. That's ultimately why it's not considered a good fighting game. It's so much fun to play, but realistically speaking, it's super broken and super unbalanced.
Here is a breakdown of some of characters and some key things they add to the game:
Eyedol is a boss character and is banned due to super strength and an infinite.
Cinder has some really stupid glitches. He is the only character that can become immune to projectiles with invisibility. He has a timed infinite that's easier to do on scaling stages. He is the only character in the game that can be controlled to glide forward or backward on a neutral jump. His air torpedo can hit as a crossover, unblockable by some characters and its direction can be changed mid flight. His flip kick is the best anti-air in the game and the light version recovers faster than almost any move in the game. The flip kick is also totally immune to projectiles. He has more combo reset options(any combo can lead into low/overhead/crossover resets that can be manually reset) than anyone in the game. He has better unbreakable combos(some with dizzy and re-dizzy abilities) than anyone in the game. The only character better than him is Eyedol.
Orchid is far and away the best character in the game if Cinder didn't exist. She is far superior to Riptor(though a good Riptor can compete, but it's like 7-3 Orchid.).
Riptor is arguably in the A tier. Some consider him B tier, but he's so far superior to that tier when used proficiently that you can't really put him in that tier. He can compete with Orchid, and give Cinder some problems if Cinder isn't invisible...but only if he catches Cinder and Orchid in his low flame trap which is inescapable.
Glacius, Sabrewulf, TJ Combo, and Spinal all compete with each other fairly well.
Jago can compete with the B tier and beats Fulgore and Thunder handily.
Fulgore exists only to beat Cinder. His crouching fierce is one of the only moves in the game that can counter Cinder's air torpedo.
Thunder is just terrible. Never ever use him...ever.